中文摘要：

为提高跨临界CO2水-水热泵系统的效率，在原有管壳式换热器的基础上，设计了新型套管式换热器，建立了新的水-水热泵系统．对带有回热器（IHX）和不带回热器的两种循环进行了实验研究．结果表明：在3种气体冷却器进水温度下，当获得中高温热水（45～70℃）时，随着气体冷却器进水温度的升高，制热系数（COPh）降低；带回热器循环的制热系数略高于不带回热器的循环，高5％～10％．

英文摘要：

In order to improve the efficiency of transcritical CO2 water-water heat pumps, new heat exchangers were designed on the basis of the original tube-and-shell heat exchanger and a new water-water heat pump system was es- tablished. A comparison was made between the cycle with internal heat exchanger （IHX） and the cycle without IHX. Experiments were done under three working conditions. Results show that when the hot water temperature ranges from 45 to 70 ℃, COPh of the cycle decreases with the increase of the inlet water temperature of the gascooler. COPh of the cycle with IHX is slightly higher than that of the cycle without IHX. The difference is about 5%-10%.